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LDN and Cellular Hypothyroidism: When TSH is Normal but Reverse T3 is Elevated


Carrie Jones, ND, MPH

Hypothyroidism is well understood in conventional medicine as an elevated TSH along with associated symptoms. Unfortunately, TSH is determine by the levels of T3 in the pituitary as determined by the type 2 deiodinase. In the periphery, type 1 deiodinase is what converts T4 into T3 while type 3 deiodinase converts T4 into reverse T3. Understanding what might cause a decrease in either type 1 or type 2 or an increase in type 3 deiodinase coupled with low dose naltrexone treatment could greatly improve lab and symptom outcomes in patients with hypothyroidism or for those who experience classical hypothyroid symptoms but have a TSH within range on a lab report.

  1. Understand the function of type 1, 2 and 3 deiodinase in relation to TSH, T4 and T3.
  2. Learn common causes that might cause an upregulated or downregulated deiodinase.
  3. Review the mechanism of action of low dose naltrexone and how this may play a role in supporting appropriate TSH, T4 and T3 levels to improve thyroid outcomes.